`dcat:contactPoint` schema and metadata refactoring

[Cryphonectria]

Issue

Originally posted by @Cryphonectria in #228

it seems that dcat:contactPoint only seems to be required for opendata.swiss - but it's not listed as required in our internal schema or for I14Y.

@hurni it's mandatory in the dcat-ap-ch standard and actually the use of of vCard is recommended. We currently use schema:name and schema:email. Fixing this will break the current metadata that use schema:name and schema:email. once we clean the metadata we can also change this to vCard and required. Ok?

➡️ ok with @bar9 ?

Steps

• Remove bad metadata
• fix schema dcat:contactPoint in in dataset.json, dataSeries.json and dataService.json to something like this:

"dcat:contactPoint": {
    "title": "Contact Point",
    "description": "**Mandatory.** Information for potential inquiries. Must be provided as a list of vCard objects (usually Organization).",
    "type": "array",
    "minItems": 1,
    "items": {
        "type": "object",
        "required": [
            "vcard:fn",
            "vcard:hasEmail"
        ],
        "properties": {
            "vcard:fn": {
                "title": "Full Name (Organization Name)",
                "description": "The formatted name of the organization or individual.",
                "type": "string"
            },
            "vcard:hasEmail": {
                "title": "Email",
                "description": "Direct email address (e.g. mailto:user@example.org).",
                "type": "string",
                "format": "email"
            },
            "vcard:hasURL": {
                "title": "Website",
                "description": "Link to a contact form or department website.",
                "type": "string",
                "format": "uri"
            }
        }
    }
}

• update metadata so the new contactPoint property works